Petco Text Logo
Petco Pet Logo

  • Two Easy Ways to Start Earning Rewards!

Neutering my dog: Fasting, weight gain, and will he be dull after?

Updated On September 23rd, 2025

Pet's info: Dog | Labrador Retriever | Male | unneutered | 1 year and 1 month old | 40 lbs

I'm thinking of neutering my dog. I consulted a doctor. He has fixed the date for Friday and asked not to feed him friday morning. The thing is I feed him at 6 am everyday. So it would be hard to keep him not fed. He'll bark until he's fed. 1. What should I do about it? 2. Is it true that he'll gain weight after neutering? 3. What should I expect after the surgery? I'm a lot worried about my dog. This is my first dog. I heard that dogs after neutering will be dull. Is it true?

1 Answer

Most Helpful Answer

Image profile

Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on March 17th, 2018

Good on you for neutering Damon! It's a very responsible decision to make, and will have many health benefits for him. He will be fine without being fed for one morning. It's imperative he is not fed or surgery cannot happen. All dogs must be fasted before surgery to prevent them from potentially regurgitating their food while under anesthesia. You may just have to deal with his barking for one morning, and it will be ok. It's temporarily. No, it's not true he will gain weight after surgery. As long as he is fed a healthy diet of dog food, doesn't get excess treats or any human food, and gets plenty of exercise, he will stay a normal weight. All my pets are spayed and neutered, and none of them have gained weight after surgery because I feed them a healthy diet and exercise them. Intact dogs can just as easily gain weight as neutered dogs if you feed them too much and don't exercise them. Dogs who are neutered are not dull afterward. I have a Basset Hound that was a former show dog, and he was about two when I first got him. He wasn't neutered at the time, and I neutered him. He is just as lively as before. You can expect that Damon will not want to roam for females to mate with, and any aggressive behaviors that are linked to hormones are usually typically eliminated with neutering. Damon will still be the same dog you had before surgery. I hope this helps :-)

Vote icon

1Pet Parents found this answer helpful

Related Questions

Petco Pet Education Center
Food & Nutrition
The vet says when the testicals operation is done he will eat more & become fat & lathargic which can be controlled if we feed him less & make him active by playing but we want him to be active like he is now & at the same time we want him to be heal
He will be just as active as before the castration. You just have to watch his weight as he does not need as much food any more (being an entire boy takes more calories). He will be just as happy as he is now and just as lively. Just feed him less than you have been feeding now. If he gains weight, reduce his feed further, and if he loses weight, feed a little more, until you have found the correct amount to keep him at his present weight.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog just got neutered and I dont know if hes ok or not. Hes acting really weird. What is usual behavior post neuter?
This really depends on what he is doing, and how long ago he was neutered. If the surgery was today, then he will likely be feeling strange and not himself for the whole evening. Depending on what kind of anesthetic drugs and pain medications he was given, he could be really whiny, needy, or just laying around. If he is really agitated, or trying to lick constantly, or seems really painful, then he may not have been given adequate pain medication and I would call your after-hours vet right away for further help. He may not be interested in food or water, and this can be normal, just for tonight. Tomorrow he should be eating and acting normally. If he is laying around and won't get up even when you stimulate him, this may be an emergency and I would call a vet right away, as this is certainly not normal. With my neuters, I always send them home the same day, fully awake, and with extra pain medication to go home with. Hope that helps!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
If I get my dog neutered how long will it take to see a difference in behavior? He"s supposed to get neutered on 8/22/17
The only behaviors that will be affected by castration are those that are under the influence of male hormones. So for example, a dog’s temperament, training, and personality, are related to genetics and upbringing, not hormones. Neutering does not “calm” an excitable dog, and unless a castrated male dog is overfed or underexercised, there is no reason for it gain weight or become inactive. The undesired traits which are related to male hormones such as sexual behaviours, aggression, and urine marking will change over the course of a few days to a few months. I hope that is helpful information and I wish you the best of luck with Nipper's surgery.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
I'm getting tux neutered soon and I want to know how to prevent the unwanted weight gain and muscle loss
Hello, you can continue to exercise Tux daily to keep him at a lean body weight. The exercise will also help keep his muscles toned. Alternatively, you can speak with your veterinarian about performing a vasectomy and not a castration. This will allow him to keep his testicles and be unable to reproduce. Most often however, dogs that maintain a regular active lifestyle with their owners will maintain a lean body weight. Hope this helps and best of luck.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Before and after neutering care for male dog.
The only before care is to make sure Thor is fasted the night before and the morning of the surgery. After surgery, he needs to be kept as quiet as possible to ensure proper healing. No running, jumping, or playing. Keep an Ecollar on him at all times to keep him from licking at his stitches. Feed him his normal diet, and his appetite should be normal 24 hours after surgery. Monitor his incision daily, and if you see signs of infection (redness, swelling, warmth to the touch, or pus), then take him into the vet for treatment. Give pain relief as prescribed by your vet, and monitor his demeanor to make sure he returns to normal. Any questions or concerns, contact your vet. Best of luck.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello and good afternoon. I want to know if castration of my Labrador Retriever (age 2 years) has any side effect or risk. I would also want to know if his behavior will change ? Will he remain same playful happy and affectionate like now? Will there
Thank you for submitting your question regarding Popo. Neutering him will help to prevent against certain types of prostate diseases and even some forms of cancer. It will decrease his desire to roam looking for female dogs. It does not affect personality. Every surgery carries the risk of anesthesia. He could experience post-operative swelling or infection. Some adult dogs can gain weight after the surgery. So his calories need to be monitored. These risks are minimal in most cases though. I hope this information helps!
Updated on September 24th, 2025
Petco Pet Education Center
Food & Nutrition
Its mating season. My male lab jumps a gate several times a day. to meet up with others dog. Since two days ago he's skinny as a stick. Could the jumping make him lose weight
The pining for females and going on a search for females takes a lot of energy and many male dogs stop eating during that time. Having him neutered will stop this and also keeping him inside and feeding him good quality food may make him gain weight again. However, having him neutered will be best to avoid him getting skinny.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hi.. I just got Mini spayed.. Before the procedure, my vet told me that if both the ovaries were to be removed, she would gain a lot of weight.. But, as per the suggestions from doctors through Boop by Petco, I went ahead n got both her ovaries remov
Hello and thank you for contacting Boop by Petco. Do no worry about the weight gain. If you feed your Mini good quality food and make sure that gets daily exercises she will not be overweight. Overweight in neutered dogs is usually caused by too rich, inexpensive diet from supermarkets. Removing one ovary is completely pointless from medical perspective. Now, after the surgery you should not allowed Mini to run, jump or go up and down the stairs. She will be ok to walk on a leash. You need to do that for about 10 days. You can feed her as normal. Please, make sure she does not lick the surgical wound. You can put a head cone on her, but if she doesn't like it you can use a baby t-shirt or buy a special recovery suit. In 10-12 days the wounds should be fully healed and you vet will probably remove her stitches.
Updated on September 24th, 2025
Petco Pet Education Center
Food & Nutrition
hi, leo has recently been neutered. how to take care of him after being fixed?and also he didn’t eat much before neutering because he was very interested in female. he lost some weights! and how to help him gain weight healthily? and he is quite pick
Most pets lose weight for an underlying reason that should be found out and treated for directly. In puppies that reason is often intestinal parasites, so I would suggest starting with a proper fecal exam through your vet. Most pets, even unneutered males, will still eat an appropriate amount of food, regardless of hormonal influence. At this weight, he should be eating around 2.5- 3 cups daily, and he should still be eating puppy food which is high in calories and ensures proper weight gain in an of itself. Some good food brands to consider for picky eaters are: Royal canin, Eukanuba, Victor, or Fromm. You just have to find a brand he likes. Appetite stimulants are only necessary for sick pets, and also arent' guaranteed to work on pets, especially ones that are just being picky. You can also try adding in canned wet food to see if that encourages him to eat better. : ) Post neuter, he should have limited activity for 10-14 days, wear an e-collar during his recovery to discou
Updated on September 24th, 2025
Petco Pet Education Center
New Pet
We adopted an 18 month old standard poodle, weighing 59 pounds. If he's neutered will he lose muscle mass or get a higher pitched bark? Will less testosterone make him more skittish around new experiences that he wasn't exposed to before, like new
It is recommended to neuter most males who are not intended for breeding. AT Teddy's age, it will not decrease muscle mass or change the pitch of his bark. Neutered males are generally considered better pets because testosterone can cause pets to be more reactive, aggressive, dominant and territorial. There are also many health benefits. Here is a link with helpful information: https://www.petcoach.co/article/benefits-of-neutering-castrating-male-dogs-puppies/ I hope this helps and please feel free to post any additional questions.
Updated on September 24th, 2025

Related Searches

Dog Food Dog Supplies Dog Health & Wellness Weight Management Dog Food Dog Treats & Chews Dog Food With Grain Wet Dog Food Premium Dog Food Dry Dog Food Veterinary Diet Dog Food Veterinary Diets Weight Management Dog Food Nutro Weight Management Dog Food Veterinary Diet Weight Management Dog Food Science Diet Weight Management Dog Food Prescription Diet Weight Management Dog Food Pure Weight Management Dog Food ProActive Health Weight Management Dog Food Nulo Weight Management Dog Food Purina ONE Weight Management Dog Food Royal Canin Veterinary Diet Weight Management Dog Food
image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Book Now

Sponsored